The treatment of central nervous system disorders by gene therapy has been hindered by the presence of the blood-brain barrier that inhibits the entry of therapeutic DNA to the brain and by the lack of gene delivery systems able to efficiently cross this barrier.

In order to remediate this problem, we propose to conjugate a highly efficient gene delivery system, diaminobutyric polypropylenimine (DAB) dendrimer, to transferrin (Tf), an iron transporter whose receptors are over-expressed on the blood-brain barrier. This novel gene delivery system has previously demonstrated its gene delivery efficacy in cancers over-expressing transferrin receptors.